[asterisk-dev] Recommendations for using a SIP stack with Asterisk

[Tzafrir Cohen]

On Tue, Nov 13, 2012 at 04:55:56PM -0600, Tilghman Lesher wrote:
> On Tue, Nov 13, 2012 at 4:37 PM, Daniel Pocock <daniel at pocock.com.au> wrote:
> > On 13/11/12 23:23, Tilghman Lesher wrote:
> >> On Tue, Nov 13, 2012 at 12:47 PM, Faidon Liambotis <paravoid at debian.org> wrote:
> >>> On 11/13/12 20:10, Russ Meyerriecks wrote:
> >>>> I don't know if any of this applies to the distribution model but as a kernel
> >>>> developer, this is almost exactly the kernel's development process.
> >>>
> >>> Not at all. Linux is not a good comparison but since you've driven the
> >>> argument there:
> >>>
> >>> Among all forks of the kernel, there are no differences in userspace
> >>> API/ABI. Can I take a stock kernel and run it on my Debian system? Sure.
> >>> Can I write an application on my Debian system and expect it to work
> >>> (both as a source and a binary) in a RHEL system/kernel? Sure.
> >>>
> >>> Will I able to compile Asterisk against a stock pjsip? Unlikely.
> >>
> >> Can you take a Debian kernel and run it on a RHEL system?  Unlikely.
> >> How about a Red Hat Enterprise package and run it on Debian?  Probably
> >> not without significant modifications.
> >
> > Sorry to knock you on this one... but you can actually boot a RHEL
> > system with a Debian kernel.  Of course there may be one or two apps you
> > have in RHEL that expect particular kernel features, but many things
> > should run if you just copy the kernel file.
> 
> Actually, in many cases, the reason to use RHEL is the support for
> hardware that the Debian project refuses to allow in their kernel.
> So, sure, it might boot... and then refuse to mount the filesystem,
> because it doesn't know anything about that disk controller.
> 
> > `alien' lets you install packages from RHEL on Debian.  If the
> > corresponding libraries are present, things work.  There may be things
> > that don't work if they depend on a really specific library version or a
> > hard coded file location.
> 
> Precisely my point.  Faidon's examples were explicitly contrived in
> order to support his point, but modify the examples slightly, and it
> all falls down.

Faidon (answering a specific point by Russ) mentioned the
kernel/userspace ABI explicitly. Not any other ABI, which is not as
stable.

The kernel required an explicit point as the kernel is monolithic. You
can't ship a package of "linux-scsi" and update it separately.
You have to update all the kernel togethere, and reboot in the process.
But you can update libfoobar independently of any program that uses it.

Thus you tend to have just a single copy of the kernel copde (on systems
that don't use u-boot, that is. Ahem). But if you're not careful you may
get quite a few copies of libfoobar hiding inside different programs.

-- 
               Tzafrir Cohen
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